The present invention relates to drive systems for motorcycles and similar vehicles, and more particularly to completely enclosed guards for such systems capable of providing continuous lubrication of the chain drive of the system during operation of the vehicle.
Enclosing structures for drive-sprocket, driven-sprocket and associated chain drives for motorcycles, such structures containing oil supplies through which the chain passes during operation of the motorcycles are disclosed in U.S. Pat. No. 3,939,730 to De Haan, patented Feb. 24, 1976; British Pat. No. 523,701, to Marchant, of July 19, 1940; and French Pat. to Oesch, No. 958,995, of Mar. 20, 1950.
The prior art, as depicted in the cited disclosures apparently appreciate the many advantages flowing from substantially encasing the drive chain and sprockets in a housing and providing oil lubrication, thereby to prolong the useful life of the chain, to minimize evaporation of the lubricant, to minimize the harmful effects of water, sand and other contaminants, to provide a measure of protection of the engine casing, the rider, and his clothing, either prior to or subsequent to the accidental breaking of the chain in operation. All of these represent hazards of varying degree under conditions where chainguards are either completely omitted, or, if provided, are not substantially complete closures for the chain-drive system.
The present invention provides the aforesaid advantages of the prior art devices inasmuch as there is provided a complete guard casing for the driving and driven sprockets and the interconnecting pipe assembly enclosing, in a preferred form, a quantity of lubricating grease through which the chain passes in operation.
However, whereas the prior art discloses flexible or other relatively movable coupling means between the front portion of the chainguard and the rear portion thereof, in accordance with my invention, the complete chainguard is relatively rigid and inflexible so that travel of the motorcycle so equipped over rough roads cannot produce or create displacement of one portion, say the rear portion, of the guard relative to the front portion. Instead, by this invention, any up and down movement of the rear wheel of the motorcycle caused by travel over rough road or terrain is accompanied by arcuate displacement of the entire guard about the front or transmission sprocket axle, the entire guard being relatively rigid and inflexible. Similarly, up and down movement of the front wheel causes arcuate displacement of the inflexible guard to be displaced arcuately, as a unit, about the rear or driven sprocket axle.
By these means, the flexible coupling sleeves, of the prior art, usually of rubber or the like, are eliminated and the consequent risk of fracture at such coupling that can occur when the rubber or similar materials become hardened and brittle through continuous vibration and exposure to the elements, rain, sleet, ice, snow and heat, is eliminated.
Another feature of the present invention resides in the ease of access to the interior of the guard assembly whereby to facilitate connecting the respective ends of the drive chain. According to this invention, one of the interconnecting pipes is constructed to be slideably adjustable over projecting integral pipe portions of the driving sprocket housing, thus exposing the interior of the guard for threading the chain over the sprockets and fastening the ends of the chain together. O-ring seals are provided at the ends of the integral pipe portions of both the driving and driven sprocket housings to effectuate grease-tight seals, as will appear.
A principal object of the invention is to provide a lubricating chainguard for a motorcycle which obviates the need for flexible coupling between any and all portions of said chainguard.
Another object of the invention is to provide such a chainguard in which easy access to the interior of the guard is readily available by selective sliding movement of an interconnecting portion joining a front or driving-sprocket casing and a rear or driven-sprocket casing.
Another object of the invention is to provide a lubricating chainguard for a motorcycle or similar vehicle which is simple in design, inexpensive to manufacture and maintain, rugged in construction, easy to assemble and efficient in operation.
These and other objects will be apparent upon study of the following descriptions taken in connection with the accompanying drawing.